openjpa-kernel/src/main/java/org/apache/openjpa/enhance/CodeGenerator.java - openjpa - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
 package org.apache.openjpa.enhance;

 import java.io.File;
 import java.io.IOException;
 import java.io.Writer;
 import java.util.List;
 import java.util.Set;
 import java.util.TreeSet;

 import org.apache.openjpa.conf.OpenJPAConfiguration;
 import org.apache.openjpa.lib.util.ClassUtil;
 import org.apache.openjpa.lib.util.CodeFormat;
 import org.apache.openjpa.lib.util.Files;
 import org.apache.openjpa.lib.util.ParameterTemplate;
 import org.apache.openjpa.lib.util.StringUtil;
 import org.apache.openjpa.meta.ClassMetaData;
 import org.apache.openjpa.meta.FieldMetaData;
 import org.apache.openjpa.meta.JavaTypes;

 /**
  * Generates Java class code from metadata.
  *
  * @author Abe White
  * @author Stephen Kim
  * @since 0.3.0
  */
 public class CodeGenerator {

     private File _dir = null;
     private CodeFormat _format = null;
     private ClassMetaData _meta = null;
     private Class _type = null;
     private ParameterTemplate _code = null;

     /**
      * Constructor. Supply configuration and class to generate code for.
      */
     public CodeGenerator(OpenJPAConfiguration conf, Class type) {
         this(conf.newMetaDataRepositoryInstance().
             getMetaData(type, null, true));
     }

     /**
      * Constructor. Supply configuration and metadata to generate code for.
      */
     public CodeGenerator(ClassMetaData meta) {
         _meta = meta;
         _type = meta.getDescribedType();
     }

     /**
      * The directory to write source to. Defaults to the current directory.
      * If the given directory does not match the package of the metadata, the
      * package structure will be created below the directory.
      */
     public File getCodeDirectory() {
         return _dir;
     }

     /**
      * The directory to write source to. Defaults to the current directory.
      * If the given directory does not match the package of the metadata, the
      * package structure will be created below the directory.
      */
     public void setDirectory(File dir) {
         _dir = dir;
     }

     /**
      * The code formatter for the generated Java code.
      */
     public CodeFormat getCodeFormat() {
         return _format;
     }

     /**
      * Set the code formatter for the generated Java code.
      */
     public void setCodeFormat(CodeFormat format) {
         _format = format;
     }

     /**
      * Return the type being generated.
      */
     public Class getType() {
         return _type;
     }

     /**
      * Return metadata for the type being generated.
      */
     public ClassMetaData getMetaData() {
         return _meta;
     }

     /**
      * Return the generated code, or null if {@link #generateCode} has not
      * been called.
      */
     public String getCode() {
         return (_code == null) ? null : _code.toString();
     }

     /**
      * Writes the generated code to the proper directory.
      */
     public void generateCode() {
         // setup parameters
         String className = ClassUtil.getClassName(_type);
         String packageName = ClassUtil.getPackageName(_type);
         String packageDec = "";
         if (packageName.length() > 0)
             packageDec = "package " + packageName + ";";

         String extendsDec = "";
         String extendsName = "";
         if (!_type.getSuperclass().getName().equals(Object.class.getName())) {
             extendsName = ClassUtil.getClassName(_type.getSuperclass());
             extendsDec = "extends " + extendsName;
         }

         String imports = getImports();
         String[] fieldCode = getFieldCode();
         String constructor = getConstructor();

         // get code template
         _code = new ParameterTemplate();
         String codeStr = getClassCode();
         if (codeStr != null) {
             _code.append(codeStr);
             _code.setParameter("packageDec", packageDec);
             _code.setParameter("imports", imports);
             _code.setParameter("className", className);
             _code.setParameter("extendsDec", extendsDec);
             _code.setParameter("constructor", constructor);
             _code.setParameter("fieldDecs", fieldCode[0]);
             _code.setParameter("fieldCode", fieldCode[1]);
         } else
             _code.append(getClassCode(packageDec, imports, className,
                 extendsName, constructor, fieldCode[0], fieldCode[1]));
     }

     /**
      * Write the generated code to the proper file.
      */
     public void writeCode()
         throws IOException {
         if (_code == null)
             return;

         File file = getFile();
         Files.backup(file, false);
         _code.write(file);
     }

     /**
      * Write the code to the specified {@link Writer}.
      */
     public void writeCode(Writer out)
         throws IOException {
         if (_code == null)
             return;

         _code.write(out);
     }

     /**
      * Return the necessary imports for the class.
      */
     private String getImports() {
         Set pkgs = getImportPackages();

         CodeFormat imports = newCodeFormat();
         String base = ClassUtil.getPackageName(_type);
         String pkg;
         for (Object o : pkgs) {
             pkg = (String) o;
             if (pkg.length() > 0 && !"java.lang".equals(pkg)
                     && !base.equals(pkg)) {
                 if (imports.length() > 0)
                     imports.endl();
                 imports.append("import ").append(pkg).append(".*;");
             }
         }
         return imports.toString();
     }

     /**
      * Returns the set of packages that needs to be imported for this code.
      */
     public Set getImportPackages() {
         Set pkgs = new TreeSet();
         pkgs.add(ClassUtil.getPackageName(_type.getSuperclass()));

         FieldMetaData[] fields = _meta.getDeclaredFields();
         for (FieldMetaData fieldMetaData : fields) {
             pkgs.add(ClassUtil.getPackageName(fieldMetaData.getDeclaredType()));
         }

         fields = _meta.getPrimaryKeyFields();
         for (FieldMetaData field : fields) {
             pkgs.add(ClassUtil.getPackageName(field.getDeclaredType()));
         }

         return pkgs;
     }

     /**
      * Return code for a primary key constructor for the given class.
      */
     private String getConstructor() {
         FieldMetaData[] fields = _meta.getPrimaryKeyFields();
         if (fields.length == 0)
             return "";

         CodeFormat cons = newCodeFormat();
         CodeFormat body = newCodeFormat();

         // public <class> (
         cons.tab().append("public ").append(ClassUtil.getClassName(_type));
         cons.openParen(true);

         // append args to constructor, and build up body at same time
         String propertyName;
         String fieldType;
         for (int i = 0; i < fields.length; i++) {
             propertyName = fields[i].getName();
             if (propertyName.startsWith("_"))
                 propertyName = propertyName.substring(1);
             fieldType = ClassUtil.getClassName(fields[i].getDeclaredType());

             if (i > 0)
                 cons.append(", ");
             cons.append(fieldType).append(" ").append(propertyName);

             if (_meta.getPCSuperclass() == null) {
                 if (i > 0)
                     body.endl();
                 body.tab(2);
                 if (propertyName.equals(fields[i].getName()))
                     body.append("this.");
                 body.append(fields[i].getName());
                 body.append(" = ").append(propertyName).append(";");
             } else {
                 // super (...);
                 if (i == 0)
                     body.tab(2).append("super").openParen(true);
                 else
                     body.append(", ");
                 body.append(propertyName);
                 if (i == fields.length - 1)
                     body.closeParen().append(";");
             }
         }
         cons.closeParen();

         cons.openBrace(2).endl();
         cons.append(body.toString()).endl();
         cons.closeBrace(2);
         return cons.toString();
     }

     /**
      * Returns the Java declaration and access method code for all declared
      * fields.
      */
     private String[] getFieldCode() {
         CodeFormat decs = newCodeFormat();
         CodeFormat code = newCodeFormat();

         FieldMetaData[] fields = _meta.getDeclaredFields();
         for (FieldMetaData fieldMetaData : fields) {
             appendFieldCode(fieldMetaData, decs, code);
         }
         fields = _meta.getDeclaredUnmanagedFields();
         for (FieldMetaData field : fields) {
             appendFieldCode(field, decs, code);
         }
         return new String[]{ decs.toString(), code.toString() };
     }

     /**
      * Append the declaration and code for the given field to the given buffers.
      */
     private void appendFieldCode(FieldMetaData fmd, CodeFormat decs,
         CodeFormat code) {
         String fieldName = fmd.getName();
         String capFieldName = StringUtil.capitalize(fieldName);
         String propertyName = fieldName;
         if (propertyName.startsWith("_"))
             propertyName = propertyName.substring(1);
         String fieldType = ClassUtil.getClassName(fmd.getDeclaredType());

         String keyType = null;
         String elementType = null;
         String paramType = "";
         if (useGenericCollections()) {
             if (fmd.getDeclaredTypeCode() == JavaTypes.COLLECTION) {
                 Class elmCls = fmd.getElement().getDeclaredType();
                 elementType = ClassUtil.getClassName(elmCls);
                 paramType = decs.getParametrizedType(
                     new String[] {elementType});
             } else if (fmd.getDeclaredTypeCode() == JavaTypes.MAP) {
                 Class keyCls = fmd.getKey().getDeclaredType();
                 Class elmCls = fmd.getElement().getDeclaredType();
                 keyType = ClassUtil.getClassName(keyCls);
                 elementType = ClassUtil.getClassName(elmCls);
                 paramType = decs.getParametrizedType(
                     new String[] {keyType, elementType});
             }
         }

         String fieldValue = getInitialValue(fmd);
         if (fieldValue == null) {
             if ("Set".equals(fieldType))
                 fieldValue = "new HashSet" + paramType + decs.getParens();
             else if ("TreeSet".equals(fieldType))
                 fieldValue = "new TreeSet" + paramType + decs.getParens();
             else if ("Collection".equals(fieldType))
                 fieldValue = "new ArrayList" + paramType + decs.getParens();
             else if ("Map".equals(fieldType))
                 fieldValue = "new HashMap" + paramType + decs.getParens();
             else if ("TreeMap".equals(fieldType))
                 fieldValue = "new TreeMap" + paramType + decs.getParens();
             else if (fmd.getDeclaredTypeCode() == JavaTypes.COLLECTION ||
                 fmd.getDeclaredTypeCode() == JavaTypes.MAP)
                 fieldValue = "new " + fieldType + paramType + decs.getParens();
             else
                 fieldValue = "";
         }
         if (fieldValue.length() > 0)
             fieldValue = " = " + fieldValue;

         boolean fieldAccess = !usePropertyBasedAccess();
         String custom = getDeclaration(fmd);
         if (decs.length() > 0)
             decs.endl();
         ParameterTemplate templ;
         if (custom != null) {
             templ = new ParameterTemplate();
             templ.append(custom);
             templ.setParameter("fieldName", fieldName);
             templ.setParameter("capFieldName", capFieldName);
             templ.setParameter("propertyName", propertyName);
             templ.setParameter("fieldType", fieldType);
             templ.setParameter("keyType", keyType);
             templ.setParameter("elementType", elementType);
             templ.setParameter("fieldValue", fieldValue);
             decs.append(templ.toString());
         } else {
             if (fieldAccess)
                 writeAnnotations(decs, getFieldAnnotations(fmd), 1);
             decs.tab().append("private ").append(fieldType).
                 append(paramType).append(" ").append(fieldName).
                 append(fieldValue).append(";");
             if (fieldAccess)
                 decs.endl();
         }

         custom = getFieldCode(fmd);
         if (code.length() > 0)
             code.afterSection();
         if (custom != null) {
             templ = new ParameterTemplate();
             templ.append(custom);
             templ.setParameter("fieldName", fieldName);
             templ.setParameter("capFieldName", capFieldName);
             templ.setParameter("propertyName", propertyName);
             templ.setParameter("fieldType", fieldType);
             templ.setParameter("keyType", keyType);
             templ.setParameter("elementType", elementType);
             templ.setParameter("fieldValue", fieldValue);
             code.append(templ.toString());
         } else {
             // getter
             if (!fieldAccess)
                 writeAnnotations(code, getFieldAnnotations(fmd), 1);
             code.tab().append("public ").append(fieldType).append(paramType).
                  append(" ");
             if ("boolean".equalsIgnoreCase(fieldType))
                 code.append("is");
             else
                 code.append("get");
             if (fieldName.length() > 1 && Character.isLowerCase(fieldName.charAt(0))
                 && Character.isUpperCase(fieldName.charAt(1))) {
                 code.append(fieldName).parens();
             } else {
                 code.append(capFieldName).parens();
             }
             code.openBrace(2).endl();
             code.tab(2).append("return ").append(fieldName).
                 append(";").endl();
             code.closeBrace(2).afterSection();

             // setter
             if (fieldName.length() > 1 && Character.isLowerCase(fieldName.charAt(0))
                 && Character.isUpperCase(fieldName.charAt(1))) {
                 code.tab().append("public void set").append(fieldName);
             } else {
                 code.tab().append("public void set").append(capFieldName);
             }
             code.openParen(true).append(fieldType).append(paramType).
                 append(" ").append(propertyName).closeParen();
             code.openBrace(2).endl();
             code.tab(2);
             if (propertyName.equals(fieldName))
                 code.append("this.");
             code.append(fieldName).append(" = ").append(propertyName).
                 append(";").endl();
             code.closeBrace(2);
         }
     }

     /**
      * Return a code template for a generated Java class.
      */
     private String getClassCode(String packageDec, String imports,
         String className, String extendsName, String constructor,
         String fieldDecs, String fieldCode) {
         CodeFormat code = newCodeFormat();
         if (packageDec.length() > 0)
             code.append(packageDec).afterSection();
         if (imports.length() > 0)
             code.append(imports).afterSection();

         code.append("/**").endl().
             append(" * Auto-generated by:").endl().
             append(" * ").append(getClass().getName()).endl().
             append(" */").endl();

         writeAnnotations(code, getClassAnnotations(), 0);
         code.append("public class ").append(className);
         if (extendsName.length() > 0)
             code.extendsDec(1).append(" ").append(extendsName);
         openClassBrace(code);

         if (fieldDecs.length() > 0)
             code.append(fieldDecs).afterSection();

         // default constructor
         code.tab().append("public ").append(className).parens();
         code.openBrace(2).endl().closeBrace(2);

         if (constructor.length() > 0)
             code.afterSection().append(constructor);
         if (fieldCode.length() > 0)
             code.afterSection().append(fieldCode);
         code.endl();

         closeClassBrace(code);

         return code.toString();
     }

     /**
      * Appends the given list of annotations to code buffer.
      */
     private void writeAnnotations (CodeFormat code, List ann,
         int tabLevel) {
         if (ann == null || ann.size() == 0)
             return;
         for (Object o : ann) {
             if (tabLevel > 0)
                 code.tab(tabLevel);
             String s = (String) o;
             code.append(s).endl();
         }
     }

     /**
      * Append the opening code-level brace to the code; this can be
      * overridden to add code to the top of the class.
      */
     protected void openClassBrace(CodeFormat code) {
         code.openBrace(1).endl();
     }

     /**
      * Append the closing code-level brace to the code; this can be
      * overridden to add code to the bottom of the class.
      */
     protected void closeClassBrace(CodeFormat code) {
         code.closeBrace(1);
     }

     /**
      * Return Java file to write to.
      */
     public File getFile() {
         String packageName = ClassUtil.getPackageName(_type);
         String fileName = ClassUtil.getClassName(_type) + ".java";

         File dir = Files.getPackageFile(_dir, packageName, true);
         return new File(dir, fileName);
     }

     /**
      * Return a copy of the internal code format.
      */
     protected CodeFormat newCodeFormat() {
         if (_format == null)
             return new CodeFormat();
         return (CodeFormat) _format.clone();
     }

     /**
      * Return a code template for the given class, or null to use the standard
      * system-generated Java code. To facilitate template reuse, the
      * following parameters can appear in the template; the proper values
      * will be subtituted by the system:
      * <ul>
      * <li>${packageDec}: The package declaration, in the form
      * "package &lt;package name &gt;;", or empty string if no package.</li>
      * <li>${imports}: Imports for the packages used by the declared
      * field types.</li>
      * <li>${className}: The name of the class, without package.</li>
      * <li>${extendsDec}: Extends declaration, in the form
      * "extends &lt;superclass&gt;", or empty string if no superclass.</li>
      * <li>${constructor}: A constructor that takes in all primary key fields
      * of the class, or empty string if the class uses datastore identity.</li>
      * <li>${fieldDecs}: Declarations of all the declared fields.</li>
      * <li>${fieldCode}: Get/set methods for all the declared fields.</li>
      * </ul> Returns null by default.
      */
     protected String getClassCode() {
         return null;
     }

     /**
      * Return code for the initial value for the given field, or null to use
      * the default generated by the system. Returns null by default.
      */
     protected String getInitialValue(FieldMetaData field) {
         return null;
     }

     /**
      * Return a code template for the declaration of the given field, or null
      * to use the system-generated default Java code.
      * To facilitate template reuse, the following parameters can appear in
      * your template; the proper values will be subtituted by the system:
      * <ul>
      * <li>${fieldName}: The name of the field.</li>
      * <li>${capFieldName}: The capitalized field name.</li>
      * <li>${propertyName}: The field name without leading '_', if any.</li>
      * <li>${fieldType}: The field's type name.</li>
      * <li>${keyType}: Key type name for maps, null otherwise.</li>
      * <li>${elementType}: Element type name for collections, null otherwise.
      * </li>
      * <li>${fieldValue}: The field's initial value, in the form
      * " = &lt;value&gt;", or empty string if none.</li>
      * </ul> Returns null by default.
      */
     protected String getDeclaration(FieldMetaData field) {
         return null;
     }

     /**
      * Return a code template for the get/set methods of the given field, or
      * null to use the system-generated default Java code.
      * To facilitate template reuse, the following parameters can appear in
      * your template; the proper values will be subtituted by the system:
      * <ul>
      * <li>${fieldName}: The name of the field.</li>
      * <li>${capFieldName}: The capitalized field name.</li>
      * <li>${propertyName}: The field name without leading '_', if any.</li>
      * <li>${fieldType}: The field's type name.</li>
      * <li>${keyType}: Key type name for maps, null otherwise.</li>
      * <li>${elementType}: Element type name for collections, null otherwise.
      * </li>
      * <li>${fieldValue}: The field's initial value, in the form
      * "= &lt;value&gt;", or empty string if none.</li>
      * </ul>
      */
     protected String getFieldCode (FieldMetaData field)
 	{
 		return null;
 	}

     /**
      * Whether to use property-based access on generated code.
      * Defaults to false (field-based).
      */
     protected boolean usePropertyBasedAccess () {
         return false;
     }

     /**
      * Return class-level annotations. Returns null by default.
      */
     protected List getClassAnnotations() {
         return null;
     }

     /**
      * Return field-level annotations. Returns null by default.
      */
     protected List getFieldAnnotations(FieldMetaData field) {
         return null;
     }

     /**
      * Whether to use generic collections on one-to-many and many-to-many
      * relations instead of untyped collections.
      *
      * Override in descendants to change default behavior.
      */
     protected boolean useGenericCollections() {
         return false;
     }

 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/
	package org.apache.openjpa.enhance;

	import java.io.File;
	import java.io.IOException;
	import java.io.Writer;
	import java.util.List;
	import java.util.Set;
	import java.util.TreeSet;

	import org.apache.openjpa.conf.OpenJPAConfiguration;
	import org.apache.openjpa.lib.util.ClassUtil;
	import org.apache.openjpa.lib.util.CodeFormat;
	import org.apache.openjpa.lib.util.Files;
	import org.apache.openjpa.lib.util.ParameterTemplate;
	import org.apache.openjpa.lib.util.StringUtil;
	import org.apache.openjpa.meta.ClassMetaData;
	import org.apache.openjpa.meta.FieldMetaData;
	import org.apache.openjpa.meta.JavaTypes;

	/**
	* Generates Java class code from metadata.
	*
	* @author Abe White
	* @author Stephen Kim
	* @since 0.3.0
	*/
	public class CodeGenerator {

	private File _dir = null;
	private CodeFormat _format = null;
	private ClassMetaData _meta = null;
	private Class _type = null;
	private ParameterTemplate _code = null;

	/**
	* Constructor. Supply configuration and class to generate code for.
	*/
	public CodeGenerator(OpenJPAConfiguration conf, Class type) {
	this(conf.newMetaDataRepositoryInstance().
	getMetaData(type, null, true));
	}

	/**
	* Constructor. Supply configuration and metadata to generate code for.
	*/
	public CodeGenerator(ClassMetaData meta) {
	_meta = meta;
	_type = meta.getDescribedType();
	}

	/**
	* The directory to write source to. Defaults to the current directory.
	* If the given directory does not match the package of the metadata, the
	* package structure will be created below the directory.
	*/
	public File getCodeDirectory() {
	return _dir;
	}

	/**
	* The directory to write source to. Defaults to the current directory.
	* If the given directory does not match the package of the metadata, the
	* package structure will be created below the directory.
	*/
	public void setDirectory(File dir) {
	_dir = dir;
	}

	/**
	* The code formatter for the generated Java code.
	*/
	public CodeFormat getCodeFormat() {
	return _format;
	}

	/**
	* Set the code formatter for the generated Java code.
	*/
	public void setCodeFormat(CodeFormat format) {
	_format = format;
	}

	/**
	* Return the type being generated.
	*/
	public Class getType() {
	return _type;
	}

	/**
	* Return metadata for the type being generated.
	*/
	public ClassMetaData getMetaData() {
	return _meta;
	}

	/**
	* Return the generated code, or null if {@link #generateCode} has not
	* been called.
	*/
	public String getCode() {
	return (_code == null) ? null : _code.toString();
	}

	/**
	* Writes the generated code to the proper directory.
	*/
	public void generateCode() {
	// setup parameters
	String className = ClassUtil.getClassName(_type);
	String packageName = ClassUtil.getPackageName(_type);
	String packageDec = "";
	if (packageName.length() > 0)
	packageDec = "package " + packageName + ";";

	String extendsDec = "";
	String extendsName = "";
	if (!_type.getSuperclass().getName().equals(Object.class.getName())) {
	extendsName = ClassUtil.getClassName(_type.getSuperclass());
	extendsDec = "extends " + extendsName;
	}

	String imports = getImports();
	String[] fieldCode = getFieldCode();
	String constructor = getConstructor();

	// get code template
	_code = new ParameterTemplate();
	String codeStr = getClassCode();
	if (codeStr != null) {
	_code.append(codeStr);
	_code.setParameter("packageDec", packageDec);
	_code.setParameter("imports", imports);
	_code.setParameter("className", className);
	_code.setParameter("extendsDec", extendsDec);
	_code.setParameter("constructor", constructor);
	_code.setParameter("fieldDecs", fieldCode[0]);
	_code.setParameter("fieldCode", fieldCode[1]);
	} else
	_code.append(getClassCode(packageDec, imports, className,
	extendsName, constructor, fieldCode[0], fieldCode[1]));
	}

	/**
	* Write the generated code to the proper file.
	*/
	public void writeCode()
	throws IOException {
	if (_code == null)
	return;

	File file = getFile();
	Files.backup(file, false);
	_code.write(file);
	}

	/**
	* Write the code to the specified {@link Writer}.
	*/
	public void writeCode(Writer out)
	throws IOException {
	if (_code == null)
	return;

	_code.write(out);
	}

	/**
	* Return the necessary imports for the class.
	*/
	private String getImports() {
	Set pkgs = getImportPackages();

	CodeFormat imports = newCodeFormat();
	String base = ClassUtil.getPackageName(_type);
	String pkg;
	for (Object o : pkgs) {
	pkg = (String) o;
	if (pkg.length() > 0 && !"java.lang".equals(pkg)
	&& !base.equals(pkg)) {
	if (imports.length() > 0)
	imports.endl();
	imports.append("import ").append(pkg).append(".*;");
	}
	}
	return imports.toString();
	}

	/**
	* Returns the set of packages that needs to be imported for this code.
	*/
	public Set getImportPackages() {
	Set pkgs = new TreeSet();
	pkgs.add(ClassUtil.getPackageName(_type.getSuperclass()));

	FieldMetaData[] fields = _meta.getDeclaredFields();
	for (FieldMetaData fieldMetaData : fields) {
	pkgs.add(ClassUtil.getPackageName(fieldMetaData.getDeclaredType()));
	}

	fields = _meta.getPrimaryKeyFields();
	for (FieldMetaData field : fields) {
	pkgs.add(ClassUtil.getPackageName(field.getDeclaredType()));
	}

	return pkgs;
	}

	/**
	* Return code for a primary key constructor for the given class.
	*/
	private String getConstructor() {
	FieldMetaData[] fields = _meta.getPrimaryKeyFields();
	if (fields.length == 0)
	return "";

	CodeFormat cons = newCodeFormat();
	CodeFormat body = newCodeFormat();

	// public <class> (
	cons.tab().append("public ").append(ClassUtil.getClassName(_type));
	cons.openParen(true);

	// append args to constructor, and build up body at same time
	String propertyName;
	String fieldType;
	for (int i = 0; i < fields.length; i++) {
	propertyName = fields[i].getName();
	if (propertyName.startsWith("_"))
	propertyName = propertyName.substring(1);
	fieldType = ClassUtil.getClassName(fields[i].getDeclaredType());

	if (i > 0)
	cons.append(", ");
	cons.append(fieldType).append(" ").append(propertyName);

	if (_meta.getPCSuperclass() == null) {
	if (i > 0)
	body.endl();
	body.tab(2);
	if (propertyName.equals(fields[i].getName()))
	body.append("this.");
	body.append(fields[i].getName());
	body.append(" = ").append(propertyName).append(";");
	} else {
	// super (...);
	if (i == 0)
	body.tab(2).append("super").openParen(true);
	else
	body.append(", ");
	body.append(propertyName);
	if (i == fields.length - 1)
	body.closeParen().append(";");
	}
	}
	cons.closeParen();

	cons.openBrace(2).endl();
	cons.append(body.toString()).endl();
	cons.closeBrace(2);
	return cons.toString();
	}

	/**
	* Returns the Java declaration and access method code for all declared
	* fields.
	*/
	private String[] getFieldCode() {
	CodeFormat decs = newCodeFormat();
	CodeFormat code = newCodeFormat();

	FieldMetaData[] fields = _meta.getDeclaredFields();
	for (FieldMetaData fieldMetaData : fields) {
	appendFieldCode(fieldMetaData, decs, code);
	}
	fields = _meta.getDeclaredUnmanagedFields();
	for (FieldMetaData field : fields) {
	appendFieldCode(field, decs, code);
	}
	return new String[]{ decs.toString(), code.toString() };
	}

	/**
	* Append the declaration and code for the given field to the given buffers.
	*/
	private void appendFieldCode(FieldMetaData fmd, CodeFormat decs,
	CodeFormat code) {
	String fieldName = fmd.getName();
	String capFieldName = StringUtil.capitalize(fieldName);
	String propertyName = fieldName;
	if (propertyName.startsWith("_"))
	propertyName = propertyName.substring(1);
	String fieldType = ClassUtil.getClassName(fmd.getDeclaredType());

	String keyType = null;
	String elementType = null;
	String paramType = "";
	if (useGenericCollections()) {
	if (fmd.getDeclaredTypeCode() == JavaTypes.COLLECTION) {
	Class elmCls = fmd.getElement().getDeclaredType();
	elementType = ClassUtil.getClassName(elmCls);
	paramType = decs.getParametrizedType(
	new String[] {elementType});
	} else if (fmd.getDeclaredTypeCode() == JavaTypes.MAP) {
	Class keyCls = fmd.getKey().getDeclaredType();
	Class elmCls = fmd.getElement().getDeclaredType();
	keyType = ClassUtil.getClassName(keyCls);
	elementType = ClassUtil.getClassName(elmCls);
	paramType = decs.getParametrizedType(
	new String[] {keyType, elementType});
	}
	}

	String fieldValue = getInitialValue(fmd);
	if (fieldValue == null) {
	if ("Set".equals(fieldType))
	fieldValue = "new HashSet" + paramType + decs.getParens();
	else if ("TreeSet".equals(fieldType))
	fieldValue = "new TreeSet" + paramType + decs.getParens();
	else if ("Collection".equals(fieldType))
	fieldValue = "new ArrayList" + paramType + decs.getParens();
	else if ("Map".equals(fieldType))
	fieldValue = "new HashMap" + paramType + decs.getParens();
	else if ("TreeMap".equals(fieldType))
	fieldValue = "new TreeMap" + paramType + decs.getParens();
	else if (fmd.getDeclaredTypeCode() == JavaTypes.COLLECTION \|\|
	fmd.getDeclaredTypeCode() == JavaTypes.MAP)
	fieldValue = "new " + fieldType + paramType + decs.getParens();
	else
	fieldValue = "";
	}
	if (fieldValue.length() > 0)
	fieldValue = " = " + fieldValue;

	boolean fieldAccess = !usePropertyBasedAccess();
	String custom = getDeclaration(fmd);
	if (decs.length() > 0)
	decs.endl();
	ParameterTemplate templ;
	if (custom != null) {
	templ = new ParameterTemplate();
	templ.append(custom);
	templ.setParameter("fieldName", fieldName);
	templ.setParameter("capFieldName", capFieldName);
	templ.setParameter("propertyName", propertyName);
	templ.setParameter("fieldType", fieldType);
	templ.setParameter("keyType", keyType);
	templ.setParameter("elementType", elementType);
	templ.setParameter("fieldValue", fieldValue);
	decs.append(templ.toString());
	} else {
	if (fieldAccess)
	writeAnnotations(decs, getFieldAnnotations(fmd), 1);
	decs.tab().append("private ").append(fieldType).
	append(paramType).append(" ").append(fieldName).
	append(fieldValue).append(";");
	if (fieldAccess)
	decs.endl();
	}

	custom = getFieldCode(fmd);
	if (code.length() > 0)
	code.afterSection();
	if (custom != null) {
	templ = new ParameterTemplate();
	templ.append(custom);
	templ.setParameter("fieldName", fieldName);
	templ.setParameter("capFieldName", capFieldName);
	templ.setParameter("propertyName", propertyName);
	templ.setParameter("fieldType", fieldType);
	templ.setParameter("keyType", keyType);
	templ.setParameter("elementType", elementType);
	templ.setParameter("fieldValue", fieldValue);
	code.append(templ.toString());
	} else {
	// getter
	if (!fieldAccess)
	writeAnnotations(code, getFieldAnnotations(fmd), 1);
	code.tab().append("public ").append(fieldType).append(paramType).
	append(" ");
	if ("boolean".equalsIgnoreCase(fieldType))
	code.append("is");
	else
	code.append("get");
	if (fieldName.length() > 1 && Character.isLowerCase(fieldName.charAt(0))
	&& Character.isUpperCase(fieldName.charAt(1))) {
	code.append(fieldName).parens();
	} else {
	code.append(capFieldName).parens();
	}
	code.openBrace(2).endl();
	code.tab(2).append("return ").append(fieldName).
	append(";").endl();
	code.closeBrace(2).afterSection();

	// setter
	if (fieldName.length() > 1 && Character.isLowerCase(fieldName.charAt(0))
	&& Character.isUpperCase(fieldName.charAt(1))) {
	code.tab().append("public void set").append(fieldName);
	} else {
	code.tab().append("public void set").append(capFieldName);
	}
	code.openParen(true).append(fieldType).append(paramType).
	append(" ").append(propertyName).closeParen();
	code.openBrace(2).endl();
	code.tab(2);
	if (propertyName.equals(fieldName))
	code.append("this.");
	code.append(fieldName).append(" = ").append(propertyName).
	append(";").endl();
	code.closeBrace(2);
	}
	}

	/**
	* Return a code template for a generated Java class.
	*/
	private String getClassCode(String packageDec, String imports,
	String className, String extendsName, String constructor,
	String fieldDecs, String fieldCode) {
	CodeFormat code = newCodeFormat();
	if (packageDec.length() > 0)
	code.append(packageDec).afterSection();
	if (imports.length() > 0)
	code.append(imports).afterSection();

	code.append("/**").endl().
	append(" * Auto-generated by:").endl().
	append(" * ").append(getClass().getName()).endl().
	append(" */").endl();

	writeAnnotations(code, getClassAnnotations(), 0);
	code.append("public class ").append(className);
	if (extendsName.length() > 0)
	code.extendsDec(1).append(" ").append(extendsName);
	openClassBrace(code);

	if (fieldDecs.length() > 0)
	code.append(fieldDecs).afterSection();

	// default constructor
	code.tab().append("public ").append(className).parens();
	code.openBrace(2).endl().closeBrace(2);

	if (constructor.length() > 0)
	code.afterSection().append(constructor);
	if (fieldCode.length() > 0)
	code.afterSection().append(fieldCode);
	code.endl();

	closeClassBrace(code);

	return code.toString();
	}

	/**
	* Appends the given list of annotations to code buffer.
	*/
	private void writeAnnotations (CodeFormat code, List ann,
	int tabLevel) {
	if (ann == null \|\| ann.size() == 0)
	return;
	for (Object o : ann) {
	if (tabLevel > 0)
	code.tab(tabLevel);
	String s = (String) o;
	code.append(s).endl();
	}
	}

	/**
	* Append the opening code-level brace to the code; this can be
	* overridden to add code to the top of the class.
	*/
	protected void openClassBrace(CodeFormat code) {
	code.openBrace(1).endl();
	}

	/**
	* Append the closing code-level brace to the code; this can be
	* overridden to add code to the bottom of the class.
	*/
	protected void closeClassBrace(CodeFormat code) {
	code.closeBrace(1);
	}

	/**
	* Return Java file to write to.
	*/
	public File getFile() {
	String packageName = ClassUtil.getPackageName(_type);
	String fileName = ClassUtil.getClassName(_type) + ".java";

	File dir = Files.getPackageFile(_dir, packageName, true);
	return new File(dir, fileName);
	}

	/**
	* Return a copy of the internal code format.
	*/
	protected CodeFormat newCodeFormat() {
	if (_format == null)
	return new CodeFormat();
	return (CodeFormat) _format.clone();
	}

	/**
	* Return a code template for the given class, or null to use the standard
	* system-generated Java code. To facilitate template reuse, the
	* following parameters can appear in the template; the proper values
	* will be subtituted by the system:
	* <ul>
	* <li>${packageDec}: The package declaration, in the form
	* "package <package name >;", or empty string if no package.</li>
	* <li>${imports}: Imports for the packages used by the declared
	* field types.</li>
	* <li>${className}: The name of the class, without package.</li>
	* <li>${extendsDec}: Extends declaration, in the form
	* "extends <superclass>", or empty string if no superclass.</li>
	* <li>${constructor}: A constructor that takes in all primary key fields
	* of the class, or empty string if the class uses datastore identity.</li>
	* <li>${fieldDecs}: Declarations of all the declared fields.</li>
	* <li>${fieldCode}: Get/set methods for all the declared fields.</li>
	* </ul> Returns null by default.
	*/
	protected String getClassCode() {
	return null;
	}

	/**
	* Return code for the initial value for the given field, or null to use
	* the default generated by the system. Returns null by default.
	*/
	protected String getInitialValue(FieldMetaData field) {
	return null;
	}

	/**
	* Return a code template for the declaration of the given field, or null
	* to use the system-generated default Java code.
	* To facilitate template reuse, the following parameters can appear in
	* your template; the proper values will be subtituted by the system:
	* <ul>
	* <li>${fieldName}: The name of the field.</li>
	* <li>${capFieldName}: The capitalized field name.</li>
	* <li>${propertyName}: The field name without leading '_', if any.</li>
	* <li>${fieldType}: The field's type name.</li>
	* <li>${keyType}: Key type name for maps, null otherwise.</li>
	* <li>${elementType}: Element type name for collections, null otherwise.
	* </li>
	* <li>${fieldValue}: The field's initial value, in the form
	* " = <value>", or empty string if none.</li>
	* </ul> Returns null by default.
	*/
	protected String getDeclaration(FieldMetaData field) {
	return null;
	}

	/**
	* Return a code template for the get/set methods of the given field, or
	* null to use the system-generated default Java code.
	* To facilitate template reuse, the following parameters can appear in
	* your template; the proper values will be subtituted by the system:
	* <ul>
	* <li>${fieldName}: The name of the field.</li>
	* <li>${capFieldName}: The capitalized field name.</li>
	* <li>${propertyName}: The field name without leading '_', if any.</li>
	* <li>${fieldType}: The field's type name.</li>
	* <li>${keyType}: Key type name for maps, null otherwise.</li>
	* <li>${elementType}: Element type name for collections, null otherwise.
	* </li>
	* <li>${fieldValue}: The field's initial value, in the form
	* "= <value>", or empty string if none.</li>
	* </ul>
	*/
	protected String getFieldCode (FieldMetaData field)
	{
	return null;
	}

	/**
	* Whether to use property-based access on generated code.
	* Defaults to false (field-based).
	*/
	protected boolean usePropertyBasedAccess () {
	return false;
	}

	/**
	* Return class-level annotations. Returns null by default.
	*/
	protected List getClassAnnotations() {
	return null;
	}

	/**
	* Return field-level annotations. Returns null by default.
	*/
	protected List getFieldAnnotations(FieldMetaData field) {
	return null;
	}

	/**
	* Whether to use generic collections on one-to-many and many-to-many
	* relations instead of untyped collections.
	*
	* Override in descendants to change default behavior.
	*/
	protected boolean useGenericCollections() {
	return false;
	}

	}